基于OFDM的高速数字传输系统的同步设计

Synchronization scheme for high speed OFDM transmission system

对于无线移动通信系统而言,多普勒频移、收发设备的本地载频偏差均可能破坏OFDM系统子载波之间的正交性,从而导致ICI,影响系统性能。另外,由于OFDM系统大多采用IFFT/FFT实现调制解调,因此在接收方确定FFT的起点对数据的正确解调也至关重要。同步技术即是针对系统中存在的定时偏差、频率偏差进行定时、频偏的估计与补偿,来减少各种同步偏差对系统性能的影响。本文主要讨论如何进行基于OFDM的高速数字系统的同步及其在FPGA上的实现。

In the wireless mobile communi and receivers will break the orthogonality significantly. Synchronization is also a vital cation of the system, the Doppler shift and the sub-channels. Thus, ICI will carrier shift between transmitters degrade the system performance factor for the correct FFT demodulation at the receiver, because IFFT/FFT the modulation and demodulation technologies are adopted in OFDM systems. The timing and frequency shifting estimate and compensate schemes in the synchronization, reducing their impact on the system performance. In this paper we propose the timing and frequency shifting estimating and compensating methods. The FPGA solution for the proposed scheme is also introduced.